CHICAGO  - US President-elect Barack Obama said Tuesday that a new dawn of American leadership was at hand and stressed the shared destiny of the United States and the rest of the world.

"It's been a long time coming. But tonight, because of what we did on this day, in this election, at this defining moment, change has come to America," he said in front of a crowd of 65,000 people.

He continued: "All of those watching tonight from beyond our shores, in the parliament and in the palaces, those huddled around radios in the forgotten corners of the world, our stories are singular but our destiny is shared."

"A new dawn of American leadership is at hand," he said to applause.

"To those who would tear the world down, we will defeat you. To those who seek peace and security, we support you."

"We have proved that the true strength of our nation comes not from the scale of our wealth but from the power of our ideals -- opportunity, democracy, liberty and hope."

He paid tribute to his campaign team, his wife, children and recently deceased grandmother.

"Along with the family that made me who I am. I miss them tonight. I know that my debt to them is beyond measure," he said.

He added: "I was never the likeliest candidate for this office. We didn't start with much money or many endorsements."

"Our campaign was not hatched in the halls of Washington. It began in the backyards of Des Moines and the living rooms and the front porches of Charleston.

First black president

Americans emphatically elected Democrat Barack Obama as their first black president Tuesday, in a transformational election which will reshape US politics and the US role on the world stage.

Obama, 47, will be inaugurated the 44th US president on January 20, 2009, and inherit an economy mired in the worst financial crisis since the 1930s, two wars in Afghanistan and Iraq and a nuclear showdown with Iran.

Television networks projected his victory over Republican John McCain after Senator Obama solidified traditional Democratic states and cut deep into the Republican territory which his rival needed to control to win the White House.

Obama's win was greeted with euphoria by a vast crowd gathered in his home city of Chicago, as his supporters, screamed, waved American flags as they waited for him to arrive to deliver his victory speech.

New York's Times Square exploded in joy at a moment of healing for America's racial scars, a huge crowd gathered outside the White House and the result immediately reverberated around the world.

Democrats also made ground in Congress, and will hold an unshakeable monopoly in power in Washington after a rare generational and political realignment.

McCain concedes defeat

McCain was gracious in defeat, and noted that his election was a moment to cherish for African Americans.

"The American people have spoken, and they have spoken clearly. A little while ago, I had the honor of calling Senator Barack Obama to congratulate him on being elected the next president of the country that we both love," he said.

"Though we fell short, the failure is mine, not yours," he told a crowd of supporters in Phoenix in his home state of Arizona.

President George W. Bush who has steered his country through eight turbulent years also congratulated Obama.

"Mr president-elect, congratulations to you," White House spokeswoman Dana Perino quoted the president as saying in a phone call to Obama.

"What an awesome night for you, your family and your supporters. Laura and I called to congratulate you and your good bride."

Bush era ends

Obama's historic inauguration will complete a stunning ascent to the pinnacle of US and global politics from national obscurity just four years ago and close an eight year era of turbulence under President George W. Bush.

Obama is promising to renew bruised ties with US allies, and to engage some of the most fierce US foes like Iran and North Korea. He has vowed to tackle climate change and provide health care to all Americans.

His presidency also marks a stunning social shift, with Obama, the son of Kenyan father and white mother from Kansas, the first African American president of a nation still riven by racial divides.

Forty-five years after civil rights icon Martin Luther King laid out his "dream" of racial equality, Obama's election broke new barriers and may have helped heal the moral wounds left by slavery and the US civil war.

When he launched his campaign on a chilly day in Illinois in February 2007, Obama forged a mantra of change which powered him throughout the longest, most costly US presidential campaign in history.

Grassroots movement

With a stunning grassroots political movement, powered by massive multi-million dollar fundraising, Obama first beat Hillary Clinton, and the Democratic Party's then preeminent political machine.

Obama strode towards victory on Tuesday by capturing the states of Pennsylvania, the key battleground which McCain needed to win to keep his long-shot hopes of victory alive.

In a sweet moment for Democrats, he also seized the midwestern battleground of Ohio and captured New Mexico and Iowa, two states won by Bush in 2004 to close out McCain's possible route towards the White House.

Obama had led national and battleground polls and had capitalized on the fear of Americans pitched into the deep financial crisis, especially as he appeared to be presidential in a string of debates.

McCain had argued that Obama was too inexperienced to be US commander in chief and would pursue "socialist" redistribution policies that would leave the economy mired in recession.

Economic crisis

McCain, 72, an Arizona senator, would have been the oldest man ever inaugurated for a first term in the White House.

Tens of millions of people had earlier stood in long lines to cast votes with America locked in a moment of deep crisis, mired in the worst financial meltdown since the 1930s and waging two foreign wars in Iraq and Afghanistan.

Obama gave early notice of the way the night would unfold by capturing the key northeastern state of Pennsylvania -- McCain's best hope of winning a Democratic state and stopping his rival from claiming the White House.

He later added Ohio, the decisive state which swept President George W. Bush to victory in 2004 and another Republican state, Virginia, which had not voted Democrat since 1964.

He also won Florida, ground zero of the 2000 recount debacle and captured other Republican states including New Mexico and Iowa.

So far he had won 27 states including his home turf of Illinois for 338 electoral votes.

McCain had won 17 but had not broken out of the Republican heartland and the south.

Senate score

In the Senate, Democrats wrested control of five Republican seats including in the traditionally Republican state of Virginia, followed by New Hampshire, North Carolina and New Mexico.

Republican Senate majority leader Mitch McConnell clung on, meaning that Democrats were highly unlikely to win the 60 seats they need in the 100-seat chamber needed to frustrate Republican obstruction tactics.

Among the Republican casualties was Elizabeth Dole in North Carolina, wife of former Senate majority leader and defeated 1996 presidential nominee Bob Dole.